Optical modulation amplitude explained

In telecommunications, optical modulation amplitude (OMA) is the difference between two optical power levels, of a digital signal generated by an optical source, e.g., a laser diode.

It is given by

OMA = P _{1} - P _{0}

where P₁ is the optical power level generated when the light source is "on," and P₀ is the power level generated when the light source is "off." The OMA may be specified in peak-to-peak mW.

The OMA can be related to the average power

P _{av} = (P _{1+P} _{0)/2} and the extinction ratio r _{e} = P _{1} /P _{0} OMA = 2 P _{av} (r _{e} -1)/(r _{e} +1)

In the limit of a high extinction ratio,

OMA ≈ 2 P _{av} . However, OMA is often used to express the effective usable modulation in a signal when the extinction ratio is not high and this approximation may not be valid.

External links

• OMA presentation by Optillion, New Orleans, September 2000